The German states of Bavaria and Rhineland-Palatinate, which have already been hit by four days of severe flooding, have been warned to expect further storms.
Water levels are expected to continue rising in both states, along with parts of North Rhine-Westphalia in the west, forecasters warned.
German Chancellor Angela Merkel paid tribute to those who had lost their lives.
"The federal government is grieving for those who received help too late," she said, adding that the response to the disaster showed how "we stick together in Germany."
About 3,500 homes in Bavaria are now without electricity after floods up to 1 meter (3.3 ft) in height struck many towns. Rescue helicopters were dispatched to Lower Bavaria rescue people from the roofs of their homes.
On Thursday, a 75-year-old resident of the Bavarian town of Simbach am Inn was confirmed dead, and the German death toll now stands at six.
The bodies of three other people were found in the same town on Wednesday evening. In nearby Julbach, the body of a woman was also discovered in a stream Wednesday evening. Four people are still missing. The death of an 86-year-old woman has also been reported in France.
German officials estimated the flood damage would likely exceed 10 million euros ($11.2 million), and Bavarian Premier Horst Seehofer pledged "quick and unbureaucratic help" for those impacted, adding that the state "won't abandon those affected, some of whom have lost their whole homes."
Flooding in France
Meanwhile, France's meteorological service said that severe flood alerts remained in effect in two Paris-area departments, while lower-threat level flood warnings were put in place in eight other departments, including three on the German border.
Floodwaters in Paris are forecast to peak on Friday with the River Seine due to reach 6m (19ft) above its normal level. Across the Paris region, thousands of people have been evacuated and some 24,400 homes were without power. The Loing River, a tributary of the Seine that runs through the French capital, has risen to levels unseen in a century, since Paris was swamped by a massive flood.
Emergency barriers have been erected in Paris to protect the city's vital infrastructure. Rail operator SNCF has been forced to close the RER C suburban underground train service that runs along the Seine.
The Louvre and Orsay museums have been shut so staff can move priceless artworks to safety.
Declaring a state of emergency for worst affected areas, French President Francois Hollande also promised money to help local authorities deal with the damage.
The torrential rains have also hit the French Open tennis tournament, washing out play earlier in the week, leaving players hoping to reach the finals facing a heavy schedule of matches
The flooding has also affected several areas of Belgium, after heavy rain hit northern Antwerp and the west of Flanders. Eastern areas around Limburg and Liege have also seen waters rise, leading to the evacuation of several neighborhoods after streets were submerged.
Schools and roads have also been flooded in Austria in recent days, though the waters have now receded.
(DW)
